Alkali metal soap thickened greases containing alkali metal salts of phenol-aldehyde condensates



Patented Sept. 4, 1962 3,052,631 ALKALI METAL SOAP THICKENED GREASESCONTAINING ALKALI METAL SALTS OF PHE- NOL-ALDEHYDE CONDENSATES Paul R.McQarthy, Allison Park, Pa., assignor to Gulf Research 8; DevelopmentCompany, Pittsburgh, Pa., a corporation of Delaware No Drawing. FiledFeb. 13, 1958, Ser. No. 714,946 9 Claims. (Cl. 25242.1)

This invention relates to lubricating compositions and more particularlyto improved grease compositions.

As is well known, lubricating greases have been made by the addition ofmetallic soaps to petroleum oils. Such greases are commonly employed tolubricate rollers and ball bearings wherein high temperatures such asabove 200 F. are frequently encountered. As would be expected, undersuch conditions the greases may tend to melt and run out of the bearingsthereby reducing the effective performance life of the grease.

The present invention has for its object to provide greases havingimproved performance life when employed to lubricate at hightemperatures.

The improved grease of the invention comprises a lubricating oil, sodiumor lithium soap and an oil-soluble metal salt of a condensation productof a substituted phenol and an aldehyde. The metal component of the saltis the same as that employed in the soap, i.e., a sodium salt isemployed with a sodium soap, and a lithium salt is employed with alithium soap.

The lubricating oil ingredient in the grease compositions provided bythis invention may be any of the hydrocarbon oils of lubricating gradesuch as those customarily used in compounding greases. While thelubricating oil in most instances is a mineral lubricating oil,synthetic lubricants such as polymerized olefins, polyalkylene oxidessuch as polypropylene oxide, polymerized glycols such as polyethyleneglycol, esters of dicarboxylic acids such as bis-(Z-ethylhexyl) sebacateand the like can be employed. The oil may be a refined or semi-refinedparaffinic-, naphthenio, or asphalt-base oil having a viscosity of about50 to 4000 Saybolt Universal seconds at 100 F. If desired, a blend ofoils of suitable viscosity may be employed instead of a single oil bymeans of which any viscosity within the range of 50 to 4000 SayboltUniversal seconds at 100 F. may be obtained. The 'oil content of thecompositions prepared according to this invention comprises about 40 toabout 95 percent or more by weight of the total composition. Theparticular oil as well as the exact amount of oil employed depends uponthe characteristics desired in the final grease composition.

The sodium or lithium soap employed in the greases of this invention maybe prepared from organic acids having between about 12 and 32 carbonatoms. The acid may be saturated or unsaturated and may containsubstituents such as hydroxyl groups. Aliphatic acids are preferred.Examples of satisfactory acids are lauric, myristic, palm-itic, stearic,arachidic, behenic, lignoceric. Mixtures of these acids or mixturesobtained by saponification of the natural fats such as cotton seed oil,lard, tallow, etc., may be used. The soaps are formed by saponifying theacid or the fat with a base such as sodium or lithium hydroxide. Ingeneral, the sodium or lithium soap content comprises about 1 to 50percent by weight of the total composition. Amounts between about andabout 25 percent are preferred.

As previously indicated, an oil-soluble sodium of lithium salt of acondensation product of a substituted phenol and an aldehyde is employedin the grease compositions of this invention. Preferably the phenolselected for reaction with the aldehyde is a substituted phenol havingan available ortho position in the ring. The substituent attached to thephenol is a hydrocarbyl radical, that is, a radical selected from amongalkyl, aryl, cycloalkyl, aralkyl and alkaryl groups.

When the substituent is an alkyl group, a straight or branched chainradical of from 4 to 18 carbon atoms is generally employed. Alkylradicals having straight or branched chains of from 6 to 12 carbon atomsare preferred. In addition, mixtures of phenols containing one or moreorthoand/ or para substituted phenols may be employed such as a mixturecontaining a variety of alkyl, cyclo-alkyl substituted phenols. Thus,the alkyl groups or other substituents on each ring in the molecule maybe different. The condensation will occur so long as there is anavailable ortho position on the phenol ring. Phenolic compounds used asstarting materials are metaor orthoand/or para-substituted alkyl, aryl,cy-cloalkyl, aralkyl and alkaryl phenols. Included are such radicals asbutyl, amyl, hexyl, octyl, nonyl, stearyl, lauryl, cyclohexyl,

methylcyclohexyl, ethylcyclohexyl, benzyl, phenyl, tolyl and xylyl. :Forthe purposes of the present invention, a preferred compound is aphenol-formaldehyde condensate having substantially the followingformula wherein n is 3 on the average:

The phenol-aldehyde condensation products can be prepared by anysuitable method and the method of preparation forms no part of thepresent invention. Usually such compounds are prepared by reacting asubstituted phenol such as an octyl phenol with an aldehyde in thepresence of an acid catalyst such as hydrogen chloride. The condensateso obtained is then converted to the sodium or lithium salt by any ofthe well known methods. For example, the condensate may be reacteddirectly with the metallic hydroxide or by a double decompositionreaction. A number of phenol-formaldehyde condensation products arecommercially available and may be utilized to produce the sodium orlithium salt included by this invention.

The amount of the sodium or lithium salt of a phenolaldehydecondensation products to be employed in the grease composition isrelatively critical in that it has been found that when these salts areemployed in the grease composition in an amount substantially below 3percent by weight, the resultant grease does not exhibit optimumcharacteristics with respect to performance life". In general, thesodium or lithium salts of the class described are employed in thegrease compositions of this invention in an amount between about 3 and10* percent or more by weight of the total composition. Amounts betweenabout 5 and about 8 are preferred.

In the greases of this invention, both the sodium and lithium soaps andthe salts of the class herein described, function to thicken thelubricating oil to the consistency of a grease. In this respect, it ispreferable to employ the selected sodium or lithium soap and thecorresponding metal salt respectively, in a ratio ranging from about11:1 to 1:1 by Weight.

The greases in accordance with the invention may be prepared using anyof the well known grease manufacturing procedures. Batch or continuousmethods of manufacture may be used. In one satisfactory method aselected fatty acid or mixture of fatty acids, a phenolaldehydecondensate and sodium or lithium hydroxide is added to a portion, as forexample, one half of a lubricating oil in a pressure vessel. The fattyacids are saponified at a pressure of about 100400 pounds per squareinch at a temperature of about 320 F. Simultaneously,

the sodium or lithium hydroxide reacts with the phenolaldehydecondensation product to produce a salt which is utilized in the greasein accordance with the invention. The reaction mass is then transferredto an open kettle for dehydration which is efie-cted by heating. Theremainder of the oil is added to this mass while heating to atemperature between 300 F. and 420 F. The mixture is then cooled toabout 200 F. If desired, other additives which will be designatedsecondary additives, are added after which the grease composition ismilled in a paint mill or colloid mill until the desired degree ofdispersion is obtained. The secondary additives which may beincorporated in the grease in order to improve specific propertiesinclude antioxidants, detergents, extreme pressure agents, rustinhibitors and the like.

Instead of forming the sodium or lithium salt of the phenol-aldehydecondensate in situ as in the above procedure, a previously prepared saltcan be added to the reaction mass at any stage of operation. Forexample, a sodium or lithium salt of a phenol-aldehyde condensate can beadded along with the secondary additives, if such are employed, prior tomilling the grease.

From the foregoing, it is apparent that the greases constituting myinvention should contain between about 1 and 50 percent of a sodium orlithium soap, preferably about and 25 percent of the specified soap,between about 3 and percent and preferably between about 5 to 8 percentof a metal salt of a condensation product of a hydrocarbyl substitutedphenol and an aldehyde, the metal component of the salt being the samemetal as present in the soap, the balance being lubricating oil andminor amounts of other additives in case such other additives aredesired.

The data given in Tables I and 11 provide a comparison of the greases ofthis invention with a conventional grease which does not contain asodium or lithium salt of the class herein disclosed. To demonstrate theincreased performance life of the greases of this invention, the greaseswere tested in an antifriction bearing test machine. This machineconsists essentially of two flatrirnmed steel wheels, each containingtwo No. 6210 ball bearings, mounted on two parallel spindles, one abovethe other, and loaded through a system of levers and fulcrum plates bytangential contact of the wheels. The lower spindle with its wheel isconnected to the loading system, 4

and the upper assembly is brought to bear upon the lower by turning downtwo large screws until it counterbalances the chosen loading weight,which in these tests was 1000 pounds. To insure a fixed temperature of250 F., the wheels are enclosed in an insulated box and heated bythermostatically controlled ring heaters surrounding the hubs. Acartridge heater in the rear of each spindle compensates for the heatloss through the heavy steel structure. Thermocouples are situated ingrooves in the spindles and contact each hearing. A pulley on the upperwheel and two appropriate holes in the side of the insulated box providefor a belt driven by means of a motor mounted on the outside. A singlecharge of grease (10 grams) is packed into each ball hearing. The testruns continue as long as the bearings remain lubricated by the originalcharge, but with several interruptions for inspections, to observedevelopments and changing conditions. Finally, the runs are terminatedand grease failure is declared when the race paths are found to be dry,a condition sometimes signalized by a sudden temperature rise in thehearing.

The lubricating oil employed in preparing these illustrative greasescomprised a mineral lubricating oil having an API gravity of 22.0, aviscosity of 510, and 54.9 Saybolt Universal seconds at 100 F. and 210F. respectively, and a flash point of 385 F. A grease was pre pared byadding to a part (approximately 35 percent) of the oil in a pressurekettle, stear-ic acid, lithium hydroxide monohydrate in aqueous solutionand the condensation product of para-isoootyl phenol and formaldehyde.The kettle contents were heated and stirred to a temperature of 320-360"F. with a resultant internal pressure in the kettle of about to 13-0pounds per square inch. Under these conditions the lithium salt of thepara-isooctyl phenol-formal=dehyde condensation product was formed andthe stearic acid was saponiiied to form the lithium soap. The kettlecontents were maintained under these conditions for one hour and thendischarged into an open kettle preheated to 350 F. Heating and stirringwere continued and the temperature of the kettle contents was raised to370-400 F. in about 3 to 4 hours. The remaining oil was slowly added atthis temperature with continued stirring. The kettle contents were thencooled with stirring to about 200 F. The cooling was continued until thetemperature reached 100-125 F. at which time the grease was milled bypassing it through a colloid mill. Utilizing the same procedure as justdescribed, a sodium grease was prepared employing sodium hydroxide inplace of the lithium hydroxide monohydrate. For comparison, a lithiumgrease was also prepared which did not contain a salt of the classincluded by this invention. Grease compositions were thus obtainedhaving the following approximate makeup:

Table I Composition, percent by Weight The Hyfac 410 utilized incomposition A is a commercially available mixture of acids of theapproximate make up:

Percent by weight Stearic acid 6'3 Palmitic acid 28 Oleic acid 6Myristic acid 3 Other grease compositions in accordance with theinvention were prepared as described above utilizing as the lubricatingoil base a mineral lubricating oil having an API of 29.8, a viscosity of315 Saybolt Universal seconds at 100 F. and 54.5 at 210 F., a flashpoint of 455 F. The greases thus obtained had the following approximatemake-up:

Table II Composition, percent by Weight D E Lubricating Oil 76.39 76. 38Sodium soap of Hydrofol 150 acids 16. 86 14. 97 Sodium salt ofp-isooctyl phenol-formaldehyde condensation product 5. 74 7. 64Antioxidant (approx. 88% diphenylamine) 1.01 1.01 Ratio Soap/Salt 2.94:1 1.96:1 Inspection:

Dropping Point F., ASIM D 566-42 417 413 Penetration, ASTM D 217-52 T-Unworked 201 175 Worked 60 Strokes 245 210 Performance TestAnti-irictionBearing Machines, 6210 Bearing, 10 grms. grease, 750 r.p.m., 1,0001b.load, 250 F Hours to Failure 5, 8,270

The Hydrofol utilized in compositions D and E is a commerciallyavailable mixture of acids of the approximate make-up:

Percent by weight Stearic acid 9O Palmitic acid 10 It is apparent fromthe foregoing data that the performance life of each of the compositionsB, C, D and E which are compositions of this invention is eminentlygreater than the performance life of composition A, which is aconventional lithium grease not containing a salt of the class describedherein. In addition to increased performance life, the greases of theinvention exhibit improved characteristics with respect to waterresistance and adhesion to metals.

It is to be noted that while the grease compositions of the inventionare particularly suited for high temperature lubricating applications,their utility is not limited thereto, and the greases of the inventioncan be advantageously utilized to lubricate where high temperatures arenot encountered.

Those modifications and equivalents which fall within the spirit of theinvention and the scope of the appended claims are to be considered partof the invention.

I claim:

1. An improved grease composition comprising a lubricating oil, about 1to about 50 percent by weight of the composition of a member of thegroup consisting of sodium and lithium soaps and about 3 to about 10percent by weight of the composition of an oil-soluble metal salt of acondensation product of a hydrocarbyl substituted phenol and analdehyde, wherein the metal constituent of the soap and the salt is thesame.

2. An improved grease composition comprising a lubricating oil, about 1to about 50 percent by weight of the composition of a member of thegroup consisting of sodium and lithium soaps and about 3 to about 10percent by weight of the composition of an oil-soluble metal salt of acondensation product of a hydrocarbyl substituted phenol and analdehyde, wherein the metal constituent of the soap and the salt is thesame and the weight ratio of said soap to said salt is between about11:1 and about 1:1.

3. An improved grease composition comprising a lubricating oil, about 1to about 50 percent by weight of the composition of a member of thegroup consisting of sodium and lithium soaps and about 3 to about 10percent by weight of the composition of an oil-soluble metal salt of thecondensation product of para-isooctyl phenol and formaldehyde, saidcondensation product containing about mols of para-isooctyl phenol permolecule of condensate, wherein the metal constituent of the soap andthe salt is the same and the weight ratio of said soap to said salt isbetween about 11: 1 and about 1:1.

4. An improved grease composition comprising a lubrication oil, about 1to about 50 percent by weight of the composition of a metal of a C to Corganic acid whose salt forming metal is selected from the groupconsisting of sodium and lithium, and about 3 to about percent by weightof the composition of an oil-soluble metal salt of the condensationproduct of para-isooctyl phenol and formaldehyde, said condensationproduct containing about 5 mols of para-isooctyl phenol per molecule ofcondensate, wherein the metal constituent of the soap and the salt isthe same and the weight ratio of said soap to said salt is between about11 :1 and about 1:1.

5. An improved grease composition comprising a Inbricating oil, about 1to about 50 percent by weight of the composition of a sodium soap of anorganic acid containing between 12 and 32 carbon atoms, and about 3 toabout 10 percent by weight of the composition of a sodium salt of thecondensation product of para-isooctyl phenol and formaldehyde, saidcondensation product containing about 5 mols of para-isooctyl phenol permolecule of condensate.

6. An improved grease composition comprising a lubricating oil, about 1to about 50 percent by weight of the composition of a lithium soap of anorganic acid containing between 12 and 32 carbon atoms, and about 3 toabout 10 percent by Weight of the composition of a lithium salt of thecondensation product of para-isooctyl phenol and formaldehyde, saidcondensation product containing about 5 mols of para-isooctyl phenol permolecule of condensate.

7. An improved grease composition comprising a lubricating oil, about 5to about 25 percent by weight of the composition of a sodium soap of anorganic acid containing between 12 and 32 carbon atoms, and about 5 toabout 8 percent by weight of the composition of a sodium salt of thecondensation product of para-isooctyl phenol and formaldehyde, saidcondensation product containing about 5 mols of para-isooctyl phenol permolecule of condensate, and the weight ratio of said soap to said saltbeing between about 11:1 and about 1:1.

8. An improved grease composition comprising a lubricating oil, about 5to about 25 percent by weight of the composition of a lithium soap of anorganic acid containing between 12 and 32 carbon atoms, and about 5 toabout 8 percent by weight of the composition of a lithium salt of thecondensation product of para-isooctyl phenol and formaldehyde, saidcondensation product containing about 5 mols of para-isooctyl phenol permolecule of condensate, and the weight ratio of said soap to said saltbeing between about 11:1 and about 1:1.

9. A method for preparing an improved lubricating grease compositionwhich comprises adding to a portion of a mineral lubricating oil, acondensation product of a substituted phenol and an aldehyde, an organicacid containing about 12 to about 32 carbon atoms and a base selectedfrom the group consisting of sodium hydroxide and lithium hydroxide,heating the mixture to a temperature of about 320 F. under a pressure ofto 300 pounds per square inch to form a soap by saponification and toform a salt by reaction of the selected base with the said condensationproduct, dehydrating the reaction mass by heating the reaction mass to atemperature of about 300 to 400 F., adding the remainder of thelubricating oil necessary to form a composition of desiredconcentration, cooling the reaction mass, milling the reaction mass toobtain a grease of desired dispersion.

References Cited in the file of this patent UNITED STATES PATENTS2,250,188 Wilson July 22, 1941 2,487,378 Roehner et al. Nov. 8, 19492,506,905 Smith et al. May 9, 1950 2,515,133 Morway July 11, 19502,545,114 Smith et al Mar. 13, 1951 2,612,474 Morgan et al. Sept. 30,1952 2,736,701 Nelf Feb. 28, 1956 2,921,904 Hotten Jan. 19, 1960 UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,052,631September 4, 1962 Paul R. McCarthy It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 1, line 25, after "011, insert a line 67, for "of" read or column2, line 11, for "cyclo alkyl" read cy'rcloadlg-yl line 45, for"productST." read product column 4, Table 1, third column, line 8, for"385" read I 375 column 5, line 57, after "metal" insert soap Signed andsealed this 8th day of January 1963,.

(SEAL) Attest:

ERNEST W SWIDER 7 DAVID L- LADD Attesting Officer Commissioner ofPatents

1. AN IMPROVED GREASE COMPOSITIONS COMPRISING A LUBRICATING OIL, ABOUT 1TO ABOUT 5 PERCENT BY WEIGHT OF THE COMPOSITION OF A MEMBER OF THE GROUPCONSISTING OF SODIUM AND LITHIUM SOAPS AND ABOUT 3 TO ABOUT 10 PERCENTBY WEIGHT OF THE COMPOSITION OF AN OIL-SOLUBLE METAL SALT OF ACONDENSATION PRODUCT OF A HYDROCARBYL SUBSTITUTED PHENOL AND ANALDEHYDE, WHEREIN THEMETAL CONSTITUENT OF THE SOAP AND THE SALTS IS THESAME.